Segmented Capacitive Input Sensing With Fewer Electrode Wires
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Solution Overview
Problem
Existing input devices with self-capacitance sensors face challenges in achieving high accuracy and reducing electrode density on a substrate, leading to increased costs and complexity due to the need for high-density wiring and multiple layers, especially when dealing with electrodes having relatively large resistance.
Innovation Solution
The input device employs a capacitance detection system with charge amplifiers and a configuration that distributes electric charges across multiple terminals of each electrode, allowing for accurate calculation of element data across segments with fewer electrodes, using a combination of high and low conductivity materials to simplify wiring and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of electrodes is increased to improve measurement precision of capacitance at multiple segments, then the electrode density and wiring complexity on the substrate increases, but this leads to increased manufacturing cost and device complexity
Solution Approach 1:
The patent divides the operation surface into multiple segments and assigns different electrodes to different segments. Each electrode has multiple terminals that are selectively connected to different segments based on the detected object's position. This segmentation allows the system to achieve high-resolution capacitance detection across multiple segments while using fewer physical electrodes, thereby reducing wiring density and manufacturing complexity.
Solution Approach 2:
The patent employs dynamic terminal connection where each electrode's terminals are selectively connected to different segments depending on the detected object's position. This dynamic reconfiguration allows a single electrode to serve multiple segments at different times, effectively reducing the total number of electrodes and wiring required while maintaining high measurement precision across all segments.
2Reliability
If the number of wiring layers is increased to achieve high-density and low-resistance wiring, then the manufacturing cost of the printed board increases
Solution Approach 1:
The patent segments the electrode connections so that each electrode's multiple terminals are connected to different segments based on detection needs. This segmentation reduces the overall wiring requirements and allows for simpler printed board designs with fewer layers, thereby reducing manufacturing cost while maintaining acceptable resistance levels through optimized connection paths.
Solution Approach 2:
The patent applies different connection configurations to different regions (segments) of the operation surface. Each segment has optimized wiring connections tailored to its specific detection requirements, allowing for lower resistance where needed without requiring high-density wiring across the entire board, thus reducing overall manufacturing cost.
3Measurement precision
If the quantity of capacitance information from each segment is increased to improve element data calculation accuracy, then the number of electrodes with overlapping portions must be increased, but this increases electrode wiring density
Solution Approach 1:
The patent uses dynamic terminal connection where electrodes can be selectively connected to different segments based on the detected object's position. This allows the same electrode to contribute capacitance information to multiple segments at different times, increasing the quantity of capacitance information available for element data calculation without increasing the physical number of electrodes or wiring density.
Solution Approach 2:
The patent changes the connection parameters (which terminal connects to which segment) dynamically based on detection needs. This parameter change allows the system to optimize the quantity of capacitance information from each electrode for different segments, improving element data calculation accuracy without requiring increased electrode density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate configuration of element data across multiple segments with fewer electrodes, reducing wiring density and complexity while maintaining high detection accuracy, even with electrodes of relatively large resistance, thus lowering production costs.
Implementation Method 1
a capacitance detection part configured to receive input of electric charges stored between the object approaching the operation surface and the electrodes, from the N terminals, and generate detection data corresponding to a capacitance between the object and the electrode
Implementation Method 2
partial electric charges stored between the object and an overlapping portion of the one of the electrodes overlapping one of the segments are distributed as distribution electric charges to each of the plurality of terminals in accordance with a conductance from the overlapping portion to each of the plurality of terminals
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A capacitance detection part 12 simultaneously receive input of electric charges stored at one electrode ER, from a plurality of terminals T provide to the one electrode ER. As a result of the simultaneous input, partial electric charges stored between an object and an overlapping portion of one electrode ER overlapping one segment A are distributed as distribution electric charges to each of the plurality of terminals T in accordance with a conductance from the overlapping portion to each of the plurality of terminals T. The capacitance detection part 12 generates detection data S corresponding to the distribution electric charges, for each of N terminals T. The element data configuration part 22 configures M pieces of element data P corresponding to M segments A, on the basis of the N pieces of detection data S.